The comparison to how many fiat currencies there are in the world kind of overlooks the fact that most of those currencies are backed by troops / armed police.
Not foreign mercenary troops either but native troops.
Not migrant swarms of troops that fly over to whichever nation offers them the biggest bounty that hour or day...
-MarkM-
So how do these troops prevent inflation?
I understand the concept of there being an established state behind most currencies and that is what gives them their value. What it doesn't stop is inflation by the state. Look at Germany in WW2. Their inflation was insane. Simply having troops does not protect you from inflation.
Actually the wonder of these crypto currencies is you don't have to look at the state backing the currency to wonder if it will have future value. The value is inherent in the system as long as there is still supply and demand moving it around in the system. Creating new systems adds total currency to the world, but it devalues other currencies as it takes patrons or value from their systems.